IIHF World U20 Championship Division I
| Most recent season or competition: 2025 IIHF U20 World Championship Division I | |
| Formerly | B-series (1979–2000) |
|---|---|
| Sport | Ice hockey |
| Founded | 1979 (B-series) 2001 (Division I) |
| No. of teams | 12 |
| Most recent champion(s) | Denmark (Group A) Ukraine (Group B) |
| Most titles | Germany (7 titles) |
| Promotion to | IIHF World U20 Championship |
| Relegation to | Division II |
| Official website | IIHF.com |
The IIHF World U20 Championship Division I is played every year among the ice hockey teams under the age of 20 who were placed in Division I in the previous year.
Until 2001 the tournament was known as the B-series.